摘要：Description of FIR FiltersFIR filters are often used because they are simple and easy to understand [6]. Diagrams of the operation of an FIR filter are shown inFigure S1. An FIR filter works by multiplying an array of the most recent n data samples by an array of constants (called the tap coefficien 阅读全文

摘要：Yesterday, I read a paper about Complex in digital communication system. I thought that was a good paper to comprehend the complex meaning in engineering. So I copied some points from this paper and made it briefer.Introduction :Quadrature signals are based on the notion of complex numbers and perha 阅读全文

摘要：The naive digital communications layer: The first layer of the onion introduces the digital transmission of data, and discusses how bits of information may be coded into waveforms, sent across space to the receiver, and then decoded back into bits. Since there is no universal clock, issues of timing 阅读全文

摘要：2011-10-02Introduce:There are two RX chennels in USRP1. It can be implementeddouble receivers by us.Abstract:Yesterday, I rewrote usrp_rx_cfile.cc to implement doublereceivers. Now, I sum up how to write a multiple antenna receivercode. I use this code to receive GSM donwlink. We can use double RXto 阅读全文

摘要：FFT信号流图： 程序实现是这样：程序流程如下图：首先进行位逆转，其实很简单，就是把二进制的位逆转过来：Matlab的位逆转程序：function a=bitreverse(Nbit, num)%Nbit = 4;%num = 8;a = 0;b = bitshift(1,Nbit-1);for i = 1:Nbit;if((bitand(num,1)) == 1)a = bitor(a,b);endnum = bitshift(num,-1);b = bitshift(b,-1);end;说明：Nbit是逆转位是几位，num是逆转的数即变量。三个循环，第一个循环是进行N阶的FFT运算第二个. 阅读全文